Cognate with Middle Dutch stel "stale" (of beer and old urine). Originally a desirable quality (in beer and wine); the meaning "not fresh" is first recorded late 15c. Figurative sense (of immaterial things) "old and trite, hackneyed" is recorded from 1560s. As a noun, "that which has become tasteless by exposure," hence "a prostitute" (in Shakespeare, etc.). Related: Staleness.